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Managing the Development of Your Overmolded Cable

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When designing a custom overmolded cable, there are several critical design details that engineers must consider such as the overmold material, physical shape, and the type of bulk cable to be used.

Design changes during development can create significant delays and cause a direct impact on program schedules, especially if hard tooling or custom bulk wire is involved. Understanding how the cables are produced and the available options to implement design updates can be the difference between completing your project on schedule or a cancelled program.

Join us for this webinar as we review overmold cable assembly material options, manufacturing processes, customization options, and more.

For more information on our custom cable assembly solutions visit http://www.epectec.com/cable-assemblies/.

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Managing the Development of Your Overmolded Cable

  1. 1. Manufacturing That Eliminates Risk & Improves Reliability Managing the Development of Your Overmolded Cable 11.21.2019
  2. 2. Manufacturing That Eliminates Risk & Improves Reliability 2 Agenda  An Overview of Overmolding  How To Design An Overmold On Your Cable  Materials and Design Options  How To Get Started With Your Custom Overmold  Summary
  3. 3. Manufacturing That Eliminates Risk & Improves Reliability 3 An Overview of Overmolding
  4. 4. Manufacturing That Eliminates Risk & Improves Reliability 4 When To Use An Overmold on Your Cable  Provide strain relief and ruggedize the connector  Replacement for an OFF THE SHELF backshell  Encapsulate delicate components, soldered connections  To provide a grip, handle or other means to mate/unmate your connection  Replace RTV, potting, or other backfilled compound  Waterproofness or environmental considerations  Cosmetic or branding for your custom cable  No EOL or Obsolesce Not all cable designs and applications warrant an overmolded cable
  5. 5. Manufacturing That Eliminates Risk & Improves Reliability 5 What is an Overmold?  Typically an injection molded process using thermoplastics  Chemical bond or “interlocked” mechanical bond between the parent material and overmold  One shot or two-shot process requiring dedicated hard tools  Innermolds are typically higher durometer for strength and to protect delicate components  Overmolds are softer and a cosmetic surface while offering strain relief High Durometer Innermold Micro-USB Connector with Innermold & Overmolded Connector Soft Overmold
  6. 6. Manufacturing That Eliminates Risk & Improves Reliability 6 How is Overmolding Performed?  Pelletized thermoplastic is poured into a hopper  Pellets are heated and fed into a network of channels, runners, and sprues  Molten thermoplastic is injected into a 2-piece tool that acts as a mold  The overmolded cable is removed from the tool  Excess material is cleaned from the overmolded cable during a visual inspection Overmolding Operation Pelletized Thermoplastic
  7. 7. Manufacturing That Eliminates Risk & Improves Reliability 7 How To Design An Overmold On Your Cable
  8. 8. Manufacturing That Eliminates Risk & Improves Reliability 8 Understanding the Tooling  Factory will design a 2-piece mold – Includes all runners, injector pins, sprue channels, etc – Materials have inherent shrink rates – Draft angles must be considered  Tolerances – Generally +/- 0.011” – Critical dimensions must be noted – Tighter tolerances are possible- but must be proved out through tooling development Bulk Cable Overmolded Backshell Off The Shelf Connector
  9. 9. Manufacturing That Eliminates Risk & Improves Reliability 9 Understanding the Tooling (cont.)  Making Changes – Changes to the connector and cable OD (outer diameter) will impact the tool – Tooling overmold design changes irreversible – Material can be removed- not added  Different Overmold Materials – Material shrink rates must be reviewed – Tool maker may require additional changes Material shrink rates are accounted for in the tooling design Tool is designed for shutoff on cable OD (outer diameter)
  10. 10. Manufacturing That Eliminates Risk & Improves Reliability 10 3D Modeling of Overmold  Customers typically supply this to Epec  Epec uses SOLIDWORKS and can design – Typically an Engineering NRE fee associated – Customer must provide design requirements  Exterior shell is critical- internals aren't – The 3D model should show the outer most surface – Internal details will be optimized by Epec – Critical features must be clearly noted .STP format is preferred for all overmold concepts Conductors Overmolded Region Overmold without Bulk Cable
  11. 11. Manufacturing That Eliminates Risk & Improves Reliability 11 Critical vs Non-Critical Features  Critical Features – Must be noted! – Critical dimensions • Max Outer Diameter (OD) or length • Bulkhead or panelized applications – Understand the mating connector  Non-Critical Features – Strain relief tapered – Custom materials – Flexibility to make tooling modifications – Ruggedized strain reliefs Allow for design flexibility with non-critical features Strain Relief Channels Are Generally Non-critical Max Outer Diameter (OD) is a Critical Dimension
  12. 12. Manufacturing That Eliminates Risk & Improves Reliability 12 2D Drawing to Define the Assembly  3D Model must be paired with a 2D drawing to define the overall assembly  Tabulated BOM – Manufacturer’s P/Ns – Usage – Source of supply – Item numbers – Customer must provide design requirements  Lengths and Tolerances  Critical Design Details Drawing must include dimensions, manufacturers P/Ns, and critical design info 2D Cable Drawing with Tabulated BOM, Lengths and Tolerances
  13. 13. Manufacturing That Eliminates Risk & Improves Reliability 13 Materials and Design Options
  14. 14. Manufacturing That Eliminates Risk & Improves Reliability 14 Material Options  Locally Sourced Compounds – Specialty materials are available, but… • Risk of sourcing challenges • MOQs • Limited manufacturing familiarity  Broad Range of Compounds Available – PVC – Polyvinyl Chloride – SR-PVC – Semi Rigid Polyvinyl Chloride – PP – Polypropylene – TPU – Polyurethane – TPE/TPR – Thermoplastic Elastomers – Polyurethane/Nylon UL approved materials are available
  15. 15. Manufacturing That Eliminates Risk & Improves Reliability 15 Material Options (cont.)  Material Compatibility – Pair PVC overmold with PVC jacket – Teflon  Some Materials Won’t Bond – Mold release – Teflon – Chemical vs Mechanical Bond  Colorization – Some materials cannot be colorized – PMS Pantone color – Color match sample Match the overmold material to the jacket Bulk Cable Jacket Conductor Jacket Overmold
  16. 16. Manufacturing That Eliminates Risk & Improves Reliability 16 Durometer  Lots Of Hardness Tests – Durometer Shore A is most common  Tolerances – +/- 5 Durometer Shore A Scale  Material Property-Inherent  If a durometer change is required, it may impact the tooling! – Must review the shrink rate of the materials Most overmolded strain relief designs are 80 – 90 Shore A Typical Durometer: 50-60 Shore A Typical Durometer: 80-90 Shore A
  17. 17. Manufacturing That Eliminates Risk & Improves Reliability 17 Plasticized PVC  PVC is a rigid and flame-retardant compound  Add plasticizers is a common way to increase flexibility  Aging and flammability are concerns  PVC hardness is expressed in P%  Example Calculation: – PVC material of 50kg – Plasticizer material of 40kg – 40kg Plasticizer / 50kg PVC =80% – Hardness is 80P Common hardness for plasticized PVC is “45P” which is about 90 Shore A
  18. 18. Manufacturing That Eliminates Risk & Improves Reliability 18  Parting lines are inherent in the process – Tool design can help minimize – Post processing is another option  Tooling marks – Ejector pins – Gate locations  Surface finish Managing the Cosmetics Optimizing gate location can help mitigate cosmetics Parting Lines Tooling Marks
  19. 19. Manufacturing That Eliminates Risk & Improves Reliability 19 Artwork in an Overmold  Company Logos  Device Information  Polarity Markings  .AI Artwork Files  Definition – Include the location – Preferred pocket depth/emboss – Layer in 3D Model Provide Logos and Artwork in .AI vectorized format ProductionInitial Design Power Ratings
  20. 20. Manufacturing That Eliminates Risk & Improves Reliability 20 Customization of Features  Implement design features to pass qualification testing – Waterproofness – Radiated / conducted emissions and susceptibility – Salt fog  Employ specialty materials, processes – Fungal resistance jacket – Encapsulate PCBA, switches, sensors – LEDs to indicate status Consider adding passive components and PCBAs to your build plan
  21. 21. Manufacturing That Eliminates Risk & Improves Reliability 21 Custom Connectors  Use 3D modeling to create desired design – Solidworks, .STP, .IGS, etc  Complete control of the design – Pin engagement – Customizable overmold  Add all those design pesky details – Beryllium copper coating to pins – Polarity markings  No EOL or Obsolesce – Custom tooling is catalogued and maintained By owning the tooling, obsolesce can be mitigated.
  22. 22. Manufacturing That Eliminates Risk & Improves Reliability 22 How To Get Started With Your Custom Build
  23. 23. Manufacturing That Eliminates Risk & Improves Reliability 23 Development Timeline Production tooling typically requires 2 - 6 weeks Proof of Concept 3D Model Samples Fit Check Production Typical Tooling Lead-Times House Tooling 0-2 weeks Simple Tooling 2-4 weeks Complex Tooling 4-8 weeks
  24. 24. Manufacturing That Eliminates Risk & Improves Reliability 24 How to Get Started with your Overmold Proof of Concept 1. 3D model of the overmold 2. 2D assembly drawing 3. Overmold material requirements 4. Critical dimensions  Varies with complexity tooling up an overmold can take 2 - 6 weeks  House tooling exists for many standard connector schemes and sizes Using house overmold tooling on Industry Connectors can save time and money
  25. 25. Manufacturing That Eliminates Risk & Improves Reliability 25 Epec Inquiry Form  When starting a project with Epec, we ask if you could please fill out our Inquiry Form.  This allows us to capture all the information of your design upfront, eliminating guess work.  Also allows us to provide you with an accurate quote.
  26. 26. Manufacturing That Eliminates Risk & Improves Reliability 26 Summary
  27. 27. Manufacturing That Eliminates Risk & Improves Reliability 27 Summary  Low cost and high reliability cable solutions  Overmolding is not for every project  Customer to provide the geometry, factory will develop the process  Dimensional changes to the overmold will require tooling rework  Specialty materials are available, but there is a potential for cost and lead-time impact
  28. 28. Manufacturing That Eliminates Risk & Improves Reliability 28 Our Products Battery Packs Flex & Rigid-Flex PCBs Cable Assemblies Printed Circuit Boards RF Products User Interfaces Flexible Heaters EC Fans & Motors
  29. 29. Manufacturing That Eliminates Risk & Improves Reliability 29 Q&A  Questions? – Enter any questions you may have in the Control Panel – If we don’t have time to get to it, we will reply via email
  30. 30. Manufacturing That Eliminates Risk & Improves Reliability 30 Thank You Check out our website at www.epectec.com. For more information email sales@epectec.com. Stay Connected with Epec Engineered Technologies Follow us on our social media sites for continuous technical updates and information:

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